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Simple Is Better When Appropriate: An Innovative Approach to Biowaste Treatment Using Wild Black Soldier Fly

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Atinuke Chineme, Marwa Shumo, Getachew Assefa, Irene Herremans and Barry Wylant

Submitted: 29 May 2023 Reviewed: 11 July 2023 Published: 16 August 2023

DOI: 10.5772/intechopen.1002449

Solid Waste Management IntechOpen
Solid Waste Management Recent Advances, New Trends and Applications Edited by Pengzhong Li

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Solid Waste Management - Recent Advances, New Trends and Applications

Pengzhong Li

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Abstract

The acknowledgement that “technology is not a panacea” creates opportunities to dialog about appropriate technologies that keep the local context at the forefront of deriving solutions. The Black Soldier Fly (BSF) biowaste treatment method offers one such opportunity, and its simplistic adaptation is critical in locations with waste collection and management challenges. In this chapter, the importance of local context on viable waste solutions will be discussed with the applicability of appropriate technology strategies. First, the Black Soldier Fly waste treatment method will be distinguished as an appropriate technology for low-income communities. Then, a brief history of the nascent BSF method will be traced, followed by the production scales favored by world regions. Finally, an open BSF bioreactor case study will be introduced and analyzed.

Keywords

  • appropriate technology
  • Black Soldier Fly
  • biowaste
  • community-based
  • open system
  • wild Black Soldier Fly
  • bioreactor
  • waste treatment
  • co-production
  • co-design

1. Introduction

The expert consensus is that municipal solid waste management (MSWM) is a global and complex task ([1], p. 9); ([2], p. 10); [3] that requires modified management techniques which depend on several factors. MWSM aims to reduce waste volume through reuse, recycling, and recovery while mitigating pollution risks. Therefore, waste management considerations include but are not limited to population, topography, climate, culture, and purchasing power (budget) of the community, city, or region. MSWM is an expensive venture and is the single highest budget line item for some low-income municipalities [4]. Governments face the challenging issue of recovering expenses from low-income communities, which is further compounded by limited municipal budgets. These obstacles make it arduous to eradicate hazardous unregulated waste disposal practices like open burning and open dumping, which are easily accessible but pose significant risks [5]. Low-income locations face additional complexities and hurdles, which include the implementation and consequent breakdown of inappropriate technologies [6], user-rejected top-down MSWM designs [7], vehicular inaccessibility due to cursory urban planning, and the scarcity of government-run facilities [8]. All these factors contribute to MSWM remaining an unresolved challenge [9], particularly in low-income regions. As such, there is a consensus that a solution to the solid waste management challenge in low-income countries must be locally developed to remain long-lasting [4, 10, 11, 12, 13]. Managing MSW involves more than just a technological system that aids in the handling and disposal of waste [14]. It incorporates the socio-economic, cultural, and operating conditions of its environment. This is where appropriate technologies come in. Appropriate technology (AT) concentrates on co-designing solutions focused on the “basic needs of water, sanitation, and agriculture” with the communities that are to be served [15]. The following section will explore the use of AT in infrastructure projects and its application in MSWM.

1.1 Appropriate technology as an alternative in solid waste management

Locally developed technologies that empower communities and build the capacities of local grassroots are conventionally deemed appropriate technologies [15]. These technologies provide necessities like water, clean air, safe and healthy food, and sanitation. “Some of the tenets generally applicable to ATs include: require little capital, utilize local materials and resources, be relatively labour intensive, be small scale and be affordable” [15]. Organizations such as the Farallon Institute in the United States stress that assistive technology (AT) should not only be affordable but also easily accessible and simple to maintain, with the ability to adapt to small-scale applications; the “socio-cultural and geographical contexts” of the location must constrain the technology. While modern and ultra-modern technologies have their place, they are not always the solution to every problem. As illustrated by Endresen and Hesselberg [16], the current modern technology deployed in mining diamonds in Botswana is inappropriate because it restricts employment instead of satisfying the urgent societal need for employment. On the other hand, using labour-intensive methods to mine diamonds (traditional methods) is equally inappropriate [16].

Appropriate technology can be traced to the post-World War II era when criticism grew over the inefficiency of technical aid support to redeveloping and developing countries [17].

To a significant degree, the American aid programs, and those of other developed nations, were captive to the notion that ideally all countries should follow the same pattern of industrialization, in both urban and rural settings…. as it turned out, such efforts ignored or misunderstood local environments, both natural and cultural…. Dams that destroyed fisheries, dual economies that privileged local elites and machinery that lay idle because of a lack of fuel or maintenance eventually led to the realization that many technologies that might be useful in donor countries might be worse than useless in different places and circumstances [17].

In the USA, the institutions created for development projects overseas and at home, like the Office of Appropriate Technology (OAT) and the National Center for Appropriate Technology (NCAT), started rolling out technologies like solar energy, low-head hydroelectricity from abandoned dams, wind energy, recycling and composting, which provided alternate development path termed AT or one of its many pseudonyms [17]. There are a variety of pseudonyms used to describe AT including progressive, alternative, light-capital, labour-intensive, indigenous, appropriate, low-cost, community, soft, radical, liberatory, and convivial technology [18, 19]. Applications in the US addressed growing skepticism about the “role of technology in American life,” thus engendering a debate that possessed significant cultural significance and ideological purpose but presented tangible and financial obstacles to established societal interests [17]. The economist E.F. Schumacher provided a framework for AT by categorizing it as intermediate technology that bridged the gap between indigenous technology and “capital-intensive technology of modern industry” [17, 18, 20]. Although apt in some regards, this characterization stigmatized AT as low-tech [21], which has proven incorrect with the recent proliferation of appropriate technologies like solar energy in all societies.

Appropriate technologies in their many forms and name have been traced back to the reign of Mao Tse-tung when it was used in rural small-scale industrialization while large-scale, capital-intensive industrialized technology was used in urban centers. In India, Mohandas Karamchand Gandhi, popularly referred to as the first appropriate technologist, shared a similar vision, “any concern with goods requires mass production, but concern with people necessitates production by the masses” [18]. His ideology inspired a group of economists in later years to found the Appropriate Technology Association of India [18].

Successes with AT in industrialized countries have yet to transfer to developing or low-income countries because conventional technical aid and development strategies operate under the notion that economic growth through industrialization equates to development [18]. This is evident in the MSWM sector, where waste-to-energy (WTE) and other advanced technologies are promoted in locations without local maintenance capacity [22]. However, recent discussions surrounding MSWM have raised concerns regarding the effectiveness of directly introducing these technologies into developing nations, considering their potential incompatibility of such regions [22].

Modern technology imposes dependence on replacement parts and linked technology, which is termed “the indivisibility of modern technology” [16]. A reliance that these low-income regions cannot afford. The capital drain on economies with tight budgets and the benefit to a minority segment of the population rather than the majority necessitates the consideration of alternative technologies in MWSM. “It is unreasonable not to promote appropriate technology for development in the traditional and informal sectors in view of the capital and foreign exchange situation in many Third World societies. Development in these regions must start with less complex and expensive techniques and move forward” [18]. At its core. AT is “context- and situation-specific,” minimizing “financial, energy, transportation, and management costs and services” while “tackling community development problems” [18, 21]. Appropriate technology is not traditional technology. Rather it encompasses technologies that are suited to the socio-cultural milieu of the society involved [16].

1.2 Local context first: Contrasting MSWM requirements in high- and low-income settings

The current determinants for using technology and sustainable waste management in high-income countries are environmental protection, climate change, diminished natural resources, and public health. On the other hand, low-income countries facing stagnated or decreasing economic growth, “unequal distribution of wealth among people, socio-cultural limitations, local and international influences, and lack of effective national policies” understandably do not share the same sense of urgency or commitment to technological solutions to MSWM [23].

Thus, “Technology should be developed in keeping with local conditions” [3, 14]. The “what,” “who,” and “how” questions remain essential to the successful adaptation and longevity of current technology [1]. The financial capability, environmental assimilative capacity, and local priorities of a country or location should be considered in the determination of the suitable MSWM system and technology [14]. Therefore, local conditions and priorities should be the final determinant of the technology developed and implemented. “Context stands for the level on which a certain technology can effectively be organized” [16]. In this regard, the location of the proposed technology determines how well the technology can be implemented, managed, and utilized. For example, the availability of waste compositional and volume data make waste-to-energy technology a viable solid waste solution in high-income communities and countries, which is not necessarily the case in low-income countries which lack reliable waste production and characterization data [23]. Technological solutions must incorporate such considerations, thus necessitating a different approach in the northern and southern hemispheres.

In relation to the local context, or local considerations, the criteria in consideration of the application of technology in MSWM should include waste volume, waste stream, affordability, operability, regulations, acceptability, environmental concerns and land availability [3]. These criteria will, therefore, be used in this section to contrast waste management strategies between high- and low-income settings. Although the discussion resolves around countries, it should be noted that high-income countries still comprise low-income communities that could benefit from solutions derived for low-income countries. Similarly, low-income countries consist of high-income communities that benefit from modern MSWM technologies. Furthermore, the presence of “large” open dumps on all continents, Africa, Asia, Europe, South America, North America and the Caribbean [23] allude to the necessity of appropriate technology in all locations across the globe.

1.2.1 Waste volume and waste streams

To a large extent, the economic status of a country determines the importance and corresponding complexity of the implemented MSWM systems. “The degree of attention paid to [MSWM system] sustainability varies from country to country and is correlated with economic status” [14]. Additionally, the economic status of a country is a strong indicator of the volume of waste generated, waste composition, and the complexity of the technology deployed [3, 4, 14, 23]. For example, the critical monitoring of waste generation increases with accuracy depending on the technology deployed. Accuracy in these measurements consequently enhances the effectiveness of the process design and the technology deployed in waste collection, transfer, treatment, and disposal. Waste production monitoring technologies developed to enhance waste collection include “geographic information systems (GISs), radio-frequency identification (RFID), ultrasonic sensors, and international system for mobile/general radio packet service (GSM/GPRS)” [23]. These technologies are available and suitable to high-income countries that can afford them while retaining the technological know-how for their operations and maintenance. However, these technologies are prohibitive in low-income countries because “untrained rag-picking is the sole method used for waste collection/segregation in about 63% of countries” [23]. This “improvised form of house-to-house collection involves a worker with a handcart who traverses each street. He rings a bell so residents can hear him coming, whereupon they leave their residences and deposit the waste in his cart. Once the handcart is full, the worker either unloads it in a community bin or deposits it in a transport vehicle” [14]. This working solution to a local waste collection challenge will prove ineffective in determining critical waste characterization and volume information. The system will provide data on transported waste but not necessarily the quantity of waste generated in the locale.

Waste generation rates, another technological determinant, vary in high- and low-income countries. For example, in 2016, low- and lower-middle-income countries contributed five and 29% of globally generated waste volumes. In contrast, upper-middle and high-income countries contributed 66% [4]. Therefore, strategies and permissible risks in the selection will significantly differ in urgency and acceptability. However, the projection that waste generation volumes in low-and lower-middle-income countries will surpass high-income countries by 2050 [4] should keep solid waste management a global priority.

Economic status is also a determining factor of the solid waste stream. Low-income countries generate more organic waste and thus will benefit more from biological technologies. Conversely, high-income countries have high recyclables with less organic waste. The low recyclable fraction is attributed to cultural and traditional practices, “In developing economies, recycling occurs at every stage of the system, leaving only a small portion that ultimately reaches the landfill for disposal” [14].

1.2.2 Affordability

A switch to biological treatment will conserve energy use and result in significant financial savings due to its associated costs and unavailability in low-income countries. “The requirement for energy is an indispensable part of modern waste-treatment facilities. According to one estimate, about 2–3% of the energy consumed by a developing country is used to treat waste. One significant remedy to this problem is changing the mode of waste-treatment from mechanical to biological” [23]. However, in high-income countries, energy use in waste management is perversive and is only conserved due to environmental protection and conservation rather than scarcity.

While labour costs are a deterrent in high-income countries, this differs in low-income countries with abundant labour resources. Approximately 30% of solid waste management costs in a treatment plant are directed to salary and maintenance [23]. Automation in these plants has helped high-income countries reduce these costs. However, low-income countries need to benefit from their people resource. Rising service and compensation costs are a concern in high-income countries but not in low-income countries. Therefore, this requires differing and unique solutions for either location’s circumstances. While the existing technologies offer benefits such as the provision of steam and electricity their long-term adverse effects on the environment, particularly in terms of greenhouse gas (GHG) emissions, diminish their appeal. Additionally, these technologies are financially demanding and necessitate infrastructure, thus limiting their feasibility, in low- and middle-income countries [23].

Capital investment in the substitution of equipment for labour thus becomes an economically justifiable action for high-income (developed) countries but not for low-income (developing and under-developed) countries.

1.2.3 Operability

Operability in the context of this discussion is synonymous with operational efficiency. Operability necessitates the safe and reliable function of the entire MSW system. Therefore, the collection, transport, transfer, recovery, treatment, and disposal of the waste needs to be efficient and reliable. For example, the use of standardized collection vehicles and procedures that are consistent with the waste characteristics and weather patterns in Calgary, Canada, had the city designing a waste management system that staggered the organic waste collection from a weekly schedule in the summer to bi-weekly in the winter and spring seasons. The cooler temperatures are used to optimize the system’s efficiency. These operational efficiency strategies are not seen in low-income countries that transport waste with a range of vehicles, from general-purpose trucks to highly mechanized compactors, which are difficult to maintain and inconsistent with the characteristics of the waste collected [14]. Attempts are being made in some locations to develop affordable collection vehicles better suited to local requirements [24]. Other design considerations that enhance operability include the availability of trained and certified workers and a MSW system design. The MSW system is designed for the long-term in high-income countries but short-term in low-income countries.

Finally, recycling in both economies have diverging approaches. Organized and cost-effective processes that leverage collaboration between public and private institutions and facilitate efficient systems are practiced in high-income countries [14]. On the other hand, the informal sector in low-income countries recovers recyclable resources from households, communities, and landfills, which are recycled through collaboration with private businesses [3, 24]. The informal sector is crucial in enhancing recycling rates, particularly in low to middle-income developing countries. The informal waste pickers collect waste from open dumpsites and streets, focusing on gathering recyclable materials and selling the valuable materials to formal or informal collection points. Consequently directly contributing to material recovery and the mitigation of environmental pollution [25].

Although well-suited to their locations, the efficiency of the informal waste recycling sector differs significantly from recycling in high-income countries, and it is difficult to quantify due to the lack of waste generation data, as mentioned earlier.

The differing technological criteria and their repute in low- and high-income settings are summarized in Table 1.

Technological considerationAttributeHigh-incomeLow-income
Waste volumeRate of waste generationHighLow
Availability and reliability of waste generation/production dataAvailable and reliableUnavailable and unreliable
Projected waste volumesReduction per capitaIncrease per capita
Waste streamWaste composition and characteristicsHigh recyclables and lower biowaste. Low density.Higher biowaste and lower recyclables. Low calorific value.
AffordabilityCapital equipment substituted for labourYes. Prompted by rising service and compensation costsNo. Informal sector dependent, hence labour dependent
OperabilityMSW system designLong-term planning. Efficient and stableExperimental
Recycling sectorWell-organized collection and processingComplex less-organized processes by small businesses and the informal sector
Technological sophisticationComplexSimple
Knowledge of the technologyTrained and certified workers are availableUnavailable trained and certified MSWM administrators
EnergyAvailableIrregular and scarce
AcceptabilityPriority of MSWM by governments and populaceHighLow
Public engagement and participationSatisfactory. Medium to highLimited. Low
Land area availabilityLand available for waste disposalLowLow
Environmental factorsIsolate landfill contents from the environmentExpensive preventative technology in use
Regulatory constraintsConstraints in technological applicationsStrict with strong enforcementWeak enforcement [2]

Table 1.

Comparing technological considerations in high and low-income countries.

Organic waste is the most substantial solid waste fraction generated in municipalities worldwide. As such, their management is essential. Organic waste, biowaste, constitute 44% of waste volumes globally [4], which means that a substantial volume of waste can be diverted and recycled by targeting this type of waste. The Black Soldier Fly (BSF) treatment, one of the many biowaste treatment methods, is an economically viable biowaste management technology due to the by-products generated [26]. Furthermore, insect-based bioconversion is a burgeoning industry that produces larvae for human and animal feed and frass biofertilizer [27]. Hence the Black Soldier Fly is introduced as a suitable biological waste treatment alternative in both high- and low-income countries.

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2. BSF technology, how it all began and why the growing interest?

The Black Soldier Fly (BSF), Hermetia illucens, is a non-pestiferous “large wasp-like fly” with exceptional biowaste management potential [28, 29, 30]. They are ravenous consumers of decaying biowaste, biodigesting double their body weight and thus recording a 50–80% biowaste volume reduction [29, 31, 32]. BSF waste treatment method is an emerging biowaste management technology used to valorize organic waste into frass biofertilizer while generating larvae for animal or human feed [27]. Studies of their application in waste management began in the 1970s but swelled at the turn of the century, with some authors citing it as a burgeoning technology [30, 33]. The economically viable by-products that BSF bioconversion produces make the technology very attractive. Mature Black Soldier Fly Larvae (BSFL), a product of the technology, contain 36–48% crude protein, 29–35% crude fat, amino acids, vitamins, and micronutrients, which makes them excellent as animal feed [28, 29, 34, 35, 36]. Entomology in biowaste management, i.e., insect farming with organic waste using BSF biotechnology, also fills the increasing demand for insect protein [35]. Various insects, including mealworms (Tenebrio molitor, Alphitobius diaperinus, and Zophobas morio), locusts (such as Locusta migratoria and Schistocerca gregaria), crickets (such as Acheta domestica and Gryllodes sigillatus), the house fly (Musca domestica), and BSF (Hermetia illucens), have been recognized as important protein contributors. However, BSF has gained notable recognition due to its remarkable ability to thrive on a wide range of organic waste materials [37].

BSF frass, the other biowaste product, is a processing residue used as a soil amendment or fertilizer [32]. The substitution of BSF frass for conventional fertilizers could reduce the global warming potential [38]. BSF are native to tropical and subtropical regions but have been noted in some temperate regions [34]. Being native to tropical and sub-tropical regions means the optimal environmental conditions for the entire BSF lifecycle are 25–32 degrees Celsius and 60% relative humidity [26]. Thus, climatic controls are required for BSF bioconversion in sub-optimal environmental conditions. This means its use in colder climates will require technological interventions that are optional in tropical climates. This makes BSF biotechnology an apt reference in analyzing location and context-specific technical application considerations.

The lifespan of a BSF begins at the egg phase (eggs laid), and it ends once the adult fly copulates and lays eggs (BSF dies) [39]. Depending on the BSF diet and environmental conditions, the time frame for the cycle from eggs, larvae, prepupae, pupae, and flies ranges between 20 and 44 days [26, 36, 37, 40, 41]. Adult flies live for about five to eight days [42], making the larvae and prepupae the most prolonged time interval for the BSF in the cycle. This feature proves advantageous in applying BSF in biotechnology as the most extended time interval of the BSFL is when they feed on biowaste. Figure 1 represents the physiological and waste management lifecycles of BSF. When viewed as a biowaste management life cycle, the cycle can be subdivided into two; BSF breeding and BSF biowaste recycling. BSF Biowaste recycling includes prepupae harvesting and frass composting. These processes are external to the BSF life cycle but deliver the economic benefits of the BSF biological waste treatment method.

Figure 1.

BSF waste treatment method in relation to BSF lifecycle.

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3. BSF solutions in high- and low-income settings

Several techniques have been employed in BSF biowaste management globally. They can be categorized into two groups, closed BSF systems based on the rearing of captive BSF and open systems, which depend on the natural oviposition of wild BSF [37]. Open systems are best-suited for low- and middle-income countries with tropical climatic conditions. In these locations, small-scale farmers, communities, and households can implement simplified units ranging from plastic trays to concrete trays and buckets [30, 37]. Although appropriate for the earlier cited application, this approach is “inefficient… to reach the desired production levels for meeting the livestock, poultry, and aquaculture feeds demand… colonization is unpredictable, resulting in lower production of BSF biomass” [37]. Therefore, the closed BSF system will be better suited for locations focusing on insect farming, i.e., BSFL as animal feed, aquaculture feed, or biofuel from the BSF fat and oil. The emphasis on BSF biomass is to obtain the maximum biowaste bioconversion. The closed system relies on the uninterrupted supply of BSF eggs from a rearing unit which is used to facilitate bioconversion with “somewhat predictable input (organic waste) and output (BSF biomass production)” [37]. Like the open system, this approach is implemented on various scales using different techniques. The main disadvantage of the closed system is the spatial requirement. Dortman et al. suggest 50 m2 for the nursery and 100 m2 for bioconversion per ton of incoming waste per day as the appropriate sizing of the BSF waste processing facility [39]. Large-scale facilities that treat 200 tonnes of waste/day for BSFL protein exist. However, information is commercially sensitive and not shared [34]. Such facilities require temperature and humidity control, automation and stable electricity and water supply, which implies increased costs available to high-income settings and the private sector. Numerous private companies are active in the production of BSF larvae. However, details about how they operate and their financial aspects are not made public. This lack of disclosure may be attributed to their desire to safeguard their competitive advantages [37]. However, one Costa Rican BSF treatment facility has been recorded as bioconverting 3 tonnes of municipal biowaste per day at a 930 m2 facility producing 3.2 kg compost per m2 per day [34].

The open system BSF biowaste treatment and biomass production are suitable for low-income communities because of their low capital investment and economic viability. Furthermore, the proposed BSF could also be sustainable, i.e., long-lasting, by integrating AT requirements. A case study, discussed in the next section, was developed by implementing an open system BSF treatment unit using AT techniques in a Dar es Salaam peri-urban community.

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4. A community-based approach to the Black Soldier Fly waste treatment system: a Tanzanian case study

Affordability, technological simplicity, adaptability to inadequate infrastructure, and profitability are essential requirements of waste management systems in low-income countries [6, 22, 43, 44]. This case study investigates the appropriateness of the Black Soldier Fly (BSF) treatment in a Tanzanian community. The intent of the study was to co-design a self-sustaining biowaste management system that advanced the environmental and personal well-being of the community in which it was installed. The location-specific appropriateness of the BSF waste treatment method was analyzed using co-production methods in the system design, generation and utilization of the BSF larvae as animal feed and in using BSF frass for farming.

4.1 Integrating appropriate technology principles in the case study

The case study approach was based on the characterization that “Appropriate technology means simply any technology that makes the most economical use of a country’s natural resources and its relative proportions of capital, labor and skills, and that furthers national and social goals” [18]. Therefore, the following criteria were employed in the design, implementation, and modification of the BSF study,

  1. Context- and location-specific,

  2. Considerate of the culture and economy,

  3. Meet and satisfy the elementary needs of the community,

  4. Stakeholder involvement in all phases of system design and operational planning and execution,

  5. Minimal “financial, energy, transportation, and management costs and services”

  6. No adverse environmental impact,

  7. Adaptable and flexible to the community’s needs,

  8. Simplified technology that is “understood, controlled and maintained without high levels of education and training.”

  9. Small-scale and affordable, and

  10. Facilitates development [21].

The investigation was subdivided into three phases to facilitate incorporating these requirements in the case study while optimally designing the BSF waste treatment. The phases correlate with co-production strategies in creating innovative public services [45]. The three phases, imitation, adaptation, and innovation, were integrated with the project design stages, as shown in Figure 2 above.

Figure 2.

Appropriate technology system design in consideration of stakeholder needs, culture, economy and local context.

4.2 Pre-design and imitation

The pre-design phase of the study was used to conduct a review of the literature to determine the regional biowaste challenges, BSF development, and key actors in the BSF waste treatment method. Based on this background study, the key design parameters for the proposed case study included a co-designed BSF bioreactor, community-led project, adequate land space for the BSF facility, predictable, consistent, and adequate source of fresh biowaste, easy access and transportation to and from the waste source, non-toxicity of the waste, BSFL, and produced frass, zero or minimal energy and water requirement, and minimum maintenance.

The researcher also conducted a pilot BSF study to gain familiarity with the technology. A design brief highlighting the particulars of the case study was produced at the end of the pre-design phase. The brief included 3D renderings of the proposed BSF facility.

4.3 Co-design and adaptation

A partnership was established with AMREF Health Tanzania, an international public health non-governmental organization (NGO) with an extensive history of sponsoring and promoting waste-to-wealth initiatives in rural and urban areas in Tanzania. AMREFs water sanitation and hygiene (WASH) manager arranged formal introductions between the researchers and the municipality officials. The meetings were opportunities to gain an understanding of the location-specific goals and requirements of the municipality. The community and waste-to-wealth community group needs were captured through an AMREF-led focus group discussion and a formal introductory meeting. The initial formal meeting with the community group came first. AMREF chaired the session introducing the research team and research objective. The BSF waste treatment technology was then described in detail using the 3D renderings from the pre-design phase to describe the project better. The group then provided suggestions for and their expectations of the project. At the end of the meeting, a site for the BSF bioreactor was determined, and agreements were made on the elementary needs that should be satisfied, including minimizing odor nuisance and long-standing project support.

Finally, the focus group discussion was used to obtain the community’s needs. Table 2 captures the researcher-based pre-design requirements and the municipal authorities and community group’s co-design requirements. All three stages were critical in the implementation of AT.

Pre-design requirementsMunicipality requirementsCommunity group requirementsCommunity requirements
Co-designed BSF bioreactor.Entire group involvement in design, planning, and operation.
Community-led project (and a project leader).Community-led with protracted technical support
Adequate land space for the BSF facility
A predictable, consistent, and adequate source of fresh organic waste
Easy access and transportation to and from the waste sourceEasy access and transportation to and from the waste source
Non-toxicity of the waste, BSFL, and produced frassNon-toxicity of the waste, BSFL, and produced frass
Zero or minimal energy and water requirement
Minimized odor nuisanceMinimized odor nuisance
Enables community developmentEnables community developmentEnables community cooperation
Manageable with household responsibilities

Table 2.

Collating the final project requirement by integrating all stakeholder requirements.

For the proposed BSF technology to truly be appropriate, the predetermined (pre-design) requirements needed modification by integrating the articulated needs of the stakeholders. The municipal authorities, community group, and community members in this instance. These needs also evolved as the project proceeded, but it was accommodated. This is the benefit of AT. A lesson learned in this instance was that although project requirements may be based on AT principles and generated from baseline studies (conducted by AMREF Health Tanzania) with extensive literature review, they can still differ from the stakeholder’s priorities.

The co-design phase also included the research team’s observations of BSF entrepreneurial activities in Dar es Salaam, visits to BSF facilities run by other organizations, discussions with waste researchers and entrepreneurs in the city, and biowaste characteristic and production pattern observations.

To satisfy the “Stakeholder involvement in all phases of system design and operational planning and execution” requirement of AT, co-design and co-production strategies were employed. Including key stakeholders in project management was encouraged and supported; co-creation and co-production made collaboration possible between the research team and the users. Co-production “is also known as co-creating services, whereby service recipients are involved in different stages of the process, including planning, design, delivery and audit of a public service” [46] and “co-creation refers to the active involvement of end-users in various stages of the production process” [47]. Both concepts focus on expanded end-user involvement as a means of incorporating as many requirements as possible and producing a product or service that is socially, economically, and environmentally appropriate, hence sustainable. “The concept co-creation and co-production seems to be related or maybe even interchangeable” [47] and as such, they will be used synonymously in this study.

“Co-production is more than mere consultations since it involves citizens/users in more systematic exchanges to create and deliver public services. Co-production transforms the relationship between service users and providers, ensuring greater user influence and ownership” [45]. The need for consultation in co-production quickly raised and resolved the community group’s desire to have all their members involved through the entire project co-design phase. This choice made them more than end-users, and they became project participators. Their active and enthusiastic commitment saw the emergence of context- and location-specific innovative solutions, which will be detailed in the post-design section.

The first nine criteria of AT prompted the redesign of the original BSF facility. A shift from a closed BSF facility to an open system was made after consultation with representatives from AMREF Health, local tradesmen (construction), BioBuu Limited, a BSF business located in Dar es Salaam, and the community group. The AT criteria for simplified technology with minimal costs made the switch apparent and the decision easy.

The original BSF facility adopted the commonly practiced closed system with a BSF rearing section (nursery) and a bioconversion section [31, 34, 39, 48, 49]. Figure 1 (closed system) and Figure 3 (open system) demonstrate how both systems are designed around the BSF life cycle and thus differ.

Figure 3.

Open system BSF waste treatment method in relation to the BSF lifecycle.

However, as noted by AT practitioners, the application of homogeneous common practice has not effectively resolved the waste treatment challenge in low-income communities. So, the pre-designed system, Figures 4 and 5, was modified.

Figure 4.

Pre-designed BSF rendering-Side view.

Figure 5.

Pre-designed BSF rendering-Aerial view.

The revised co-created and co-produced BSF bioreactor, Figures 6 and 7, harnessed the resources naturally available to the group and location, like biowaste and wild BSF. Using wild BSF eliminated the need for a nursery, thus simplifying the BSF waste treatment system. Some elements of the pre-designed requirements were carried over, like a water channel around the bioreactor to deter predators, a leachate collection system to minimize the environmental impact of the treatment system, and chicken wire to exclude larger avian organisms.

Figure 6.

The co-created BSF bioreactor.

Figure 7.

Case study BSF bioreactor schematics.

Finally, adaptation in the co-design was palpable through the development and execution of the operational plan. The community group nominated a project leader based on the research team’s recommendation of a project champion. The group traditionally elected a leader to new projects, which was a point of synergy between the research team and the community group. The project leaders, a woman and a man, were present at the BSF bioreactor during all the visits, and they ensured that information was communicated daily to the larger community group.

The consensus from the introductory meeting, focus group discussions, scoping sessions, and information from the pre-design literature review resulted in developing an operational plan that collected biowaste from surrounding households. This strategy proved unsuccessful because homes in the location practised direct-use waste management. This is the feeding of biowaste to household livestock. As such, the waste volumes collected for the first month of the project were minimal. An optimal solution was derived by engaging with the community group using co-production strategies. This involved gathering fruit and vegetable waste from retail vendors at a nearby market, transporting the waste via tricycle to the BSF bioreactor, Figure 8, and adding the waste to the bin, Figure 9. The vendors typically had to pay for the waste collected once a week for transport to a landfill by the municipal authorities. By collecting the leftovers from the vendors just before midnight, at the end of the market day, the vendors eliminated waste collection fees, and biowaste was diverted from the landfill. Waste collection volumes increased from 41 kg/week to 365 kg/week in the first month. Thereafter, due to the enthusiasm and encouragement of the community group, waste collection volumes increased to 460 kg/week. Other aspects of the project where co-production strategies were used to accomplish AT include the marketing and sales of the Black Soldier Fly Larvae (BSFL) and frass. As a result, the community became the largest customer of the products, and a member of the community group who is a farmer is currently the only beneficiary of the BSF frass.

Figure 8.

Waste collected from the retail vendors is transported with a tricycle and weighed.

Figure 9.

The biowaste is accumulated for three weeks in alternating sections of the bioreactor.

4.4 Post-design and innovation

The post-design phase purposed two-fold objectives; the autonomous management of the BSF bioreactor by the community group and the identification of technological and operational improvements to the pre-designed system. Six cycles of BSF waste treatment were run between October 2022 and April 2023, and improvements were observed with the increasing number of cycles. The procedures followed for each cycle differed, with each cycle becoming an improved version of the prior cycle. For example, cycles 3 and 4 differed significantly because the community gained semi-autonomous control of the operations and was in complete control by cycle 5. The research team strictly visited the site during these cycles for observation and data collection. In addition, the frass by-product became the highest-demand product from the BSF system. A productive BSF frass Chinese cabbage harvest resulted in the farmer, a community group leader, expanding the cultivated frass-applied land from 2 m × 6 m to 6.8 m × 12 m. The BSF bioreactor is located close to community farmland, Figure 10 and farmers in the neighboring area have requested frass.

Figure 10.

Neighboring farmland. BSF bioreactor is located with the white building in the background on the right.

The lessons learned, and improvements made over each cycle are summarized in Table 3 and categorized by AT criteria.

Appropriate technology criteria [21]Cycle 1 (Oct–Nov)Cycle 2 (Nov–Dec)Cycle 3 (Dec–Jan)Cycle 4 (Jan–Feb)Cycle 5 (Feb–Mar)Cycle 6 (Mar–Apr)
1. Context- and location-specificCo-design BSF unitShift to market wasteCo-produced leachate collection system
2. Considerate of culture and economyAppropriate permission was requested and granted from families of the women collecting waste at nighttime
3. Meet and satisfy the elementary needs of the communityBSFL used by the communityFrass used on farms
4. Stakeholder involvement in all phasesStakeholders involved.Stakeholder semi-autonomousStakeholder autonomous
5. Minimal costsYes, from cycle to cycle.
6. No adverse environmental impactYes, across all cycles.
7. Adaptable and flexible to community needsWaste collection volumes dictated by communityWaste collection frequency is controlled by the community
8. Simplified technologyBSF unit run with communityBSF unit run by the community aloneFrass drying unit co-produced
9. Small-scale and affordableYes
10. Facilitates the developmentBSF project leaders trainedCommunity group leaders trained other members on the BSF systemCommunity designing BSF training centre. Interviewed on national

Table 3.

Appropriate technology categorized improvements by BSF cycle.

Modifications suggested and implemented by the community group in the innovation phase also include the addition of an outlet valve for cleaning soapy water in the trench surrounding the BSF bioreactor. The channel was built to deter rodents and predators that feed on the BSFL. Observations of BSF projects in the city revealed predators as an existent threat. Therefore, the water-filled trench was necessary, but surfactants were needed to prevent a hospitable breeding ground for mosquitoes. However, the weather conditions made algae thrive in the channel. Weekly operations, therefore, included manually cleaning the trench, which was arduous. The community group proposed installing a valve, Figure 11, which simplified weekly maintenance and increased the project viability.

Figure 11.

Trench outlet valve designed and implemented by the community group.

Other innovations by the community group include a co-designed drying unit for wet harvested frass, weather- and rising ground water-proof leachate collection system, and BSF knowledge-sharing activities.

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5. Conclusion

Waste management is as complex as populations are diverse. Solutions vary by region, income, season, and available technology. There exists a plethora of theoretical and practiced waste management solutions. However, no sustainable—economically, socially, and environmentally acceptable solution has emerged for low-income settings. Communities and countries with limited purchasing power have relied on the same technologies available to higher-income locations, resulting in abandoned MSW projects, persistent open dumping, and open burning.

Appropriate Technology has helped create a framework that enables technological application but with the careful long-term consideration of the stakeholder’s culture, finances, environment, and social requirements. The Black Soldier Fly waste technology system is an ideal candidate for AT in low-income communities. The technology is used in various parts of the world at diverse scales, and it is flexible and adaptable enough to accommodate all AT requirements. It was successfully applied in a peri-urban Tanzanian location by members of a community group. The study is ongoing, but interest in BSF waste treatment is continuously growing in East Africa. The animal feed by-product (BSFL) and soil conditioner have proven successful in the case study and many others.

Food insecurity is a familiar concern for the future. However, people in low-income communities have raised their livestock for centuries, and BSF waste treatment allows communities to continue enjoying their traditions for centuries to come. AT with BSF waste treatment system is not a blanket solution to biowaste treatment for all low-income communities in every instance. But the combination hopefully encourages practitioners to consider all technological solutions, specifically the less advanced ones, because they might be the best-suited solution for the application. Finally, having multiple stakeholder categories involved in a project is arduous. Therefore, implementing AT criteria with co-design and co-production requirements using simple yet adaptable technology is a formidable challenge. Replicating technology becomes a more attractive option in the face of this daunting proposition. However, the longevity and productivity of the AT-produced technology more than make up for the time spent generating the lasting solution.

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Acknowledgments

This research was funded by the SOCIAL SCIENCES AND HUMANITIES RESEARCH COUNCIL, grant number 752-2022-1768 and Bioreactor Construction was funded by THE SCHOOL OF ARCHITECTURE, LANDSCAPE, AND PLANNING at THE UNIVERSITY OF CALGARY by the Research Expenses Award. The results published in this article is possible due to collaboration with AMREF Health Tanzania, Biobuu Limited, The International Institute of Tropical Agriculture (IITA) Tanzania, and Green Composting Limited.

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Conflict of interest

The authors declare no conflict of interest.

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Notes/thanks/other declarations

We are thankful for the support of the many who made this research possible including Dillion Consulting, SWANA Northern Lights Chapter, Air & Waste Management Association (A&WMA), the members of Sauti ya Jamii Kipunguni, Grace Kisetu of Hema Homes, Dr. Steve Mbuligwe of Arhdi University, Dr. Mike Yhedgo, and Aliceanna Shoo, Mturi James, Anthony Ndjovu, Dr. Frida Ngalesoni, and Jane Tesha of AMREF Health Tanzania.

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Written By

Atinuke Chineme, Marwa Shumo, Getachew Assefa, Irene Herremans and Barry Wylant

Submitted: 29 May 2023 Reviewed: 11 July 2023 Published: 16 August 2023

© The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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